sun/jvmstat/monitor/MonitoredVm/MonitorVmStartTerminate.java timeouts in the Valhalla CI on windows-x64 when the -XX:+UseCompactObjectHeaders option is used:

#section:main
----------messages:(12/681)----------
command: main MonitorVmStartTerminate
reason: User specified action: run main/othervm/timeout=240 MonitorVmStartTerminate
started: Tue Jan 13 00:40:02.903 UTC 2026
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules java.management,jdk.internal.jvmstat --add-exports jdk.internal.jvmstat/sun.jvmstat.monitor=ALL-UNNAMED --add-exports jdk.internal.jvmstat/sun.jvmstat.monitor.event=ALL-UNNAMED
Process id: 17076
Timeout information:
[00:56:02.918] starting timeout handler action(s)
[01:13:25.681] timeout handler action(s) completed
--- Timeout information end.
finished: Tue Jan 13 01:13:25.683 UTC 2026
elapsed time (seconds): 2002.78
----------configuration:(5/228)----------
Boot Layer
  add modules: java.management jdk.internal.jvmstat
  add exports: jdk.internal.jvmstat/sun.jvmstat.monitor ALL-UNNAMED
               jdk.internal.jvmstat/sun.jvmstat.monitor.event ALL-UNNAMED

----------System.out:(1887/100397)*----------
started=0, terminated=0
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_0
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_1
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_2
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_3
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_4
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_5
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_6
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_7
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_8
Starting fe5134ed-01d9-42eb-9419-a97b9cbcede4_9
Waiting for all processes to get started notification

<snip>

This test generates so much output that the log is elided.
There may be something important hiding in there...

<snip>

releaseStarted([99952])
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
hasMainArgs(99952): has main args: 'jstack --pid 17076'
releaseStarted: not a test pid: 99952
releaseTerminated([])
started=0, terminated=8
----------System.err:(24/1760)----------
Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_6 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_6 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_6 has been removed in 1503374962320 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_0 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_0 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_0 has been removed in 1504392137070 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_7 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_7 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_7 has been removed in 1503429512140 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_5 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_5 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_5 has been removed in 1503366624630 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_2 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_2 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_2 has been removed in 1503680418730 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_1 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_1 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_1 has been removed in 1503345979040 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_3 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_3 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_3 has been removed in 1503273039030 ns

Java Process fe5134ed-01d9-42eb-9419-a97b9cbcede4_4 stdout:Waiting for fe5134ed-01d9-42eb-9419-a97b9cbcede4_4 to be removed
waitForRemoval: fe5134ed-01d9-42eb-9419-a97b9cbcede4_4 has been removed in 1503577652990 ns

----------rerun:(50/7075)*----------


I don't know the details about this test, but there are number
of lines like this in the output:

hasMainArgs(99952): has main args: 'jstack --pid 17076'
releaseStarted: not a test pid: 99952
releaseTerminated([])
started=0, terminated=8

releaseStarted reports "ot a test pid: 99952", but that value
is reported in the previous "hasMainArgs(NNNN)" output lines.
What does that mean?

Each group always ends with "started=0, terminated=8"
and those values don't seem to change.

Why does this test only fail on windows-x64 and only when
the -XX:+UseCompactObjectHeaders option is used?

I recommend getting a complete passing log from another
platform, generating a complete failing log on windows-x64
and checking for any glaring differences.

Since this appears to be an issue with -XX:+UseCompactObjectHeaders